Process for the continuous manufacture of cellulose films.



EDWIN BRANDENBERGER, OF

THAON-LES-VOSGES, FRANCE.

IPROCESS FOR THE CONTINUOUS MANUFACTURE OF CELLULOSE FILMS.

means of which it is possible to obtain in a continuous m'anner films ofan indefinite length, starting direct from a water solutionof'cellulose, more particularly from a solution of cellulose Xanthate.

The process is characterized by the immediate coagulation of thecellulose water solution on its coming out from a distribu tlng hopper,by means for instance of a concentrated water solution of sulfate ofammonia or. of other suitable salts; the film thus f immediately athand, of removing all d by coagulation ',-b,eing

the 1m ifes formed, I polysulfids and on the other hand of rendering thesaid film insoluble in water, the film thus ren- L dered insoluble beingfinally washed in cold salts.

and in hot water,

- For carrying out the above process in practice, the cellulose watersolution is dis. tributed in the shape of a layer by means of a suitablehopper. It is immediately coagulated by a concentrated water solution ofsulfate of ammonia or of other suitable The cellulose/layer or""'sh'eetis immediately converted into a cellulose film covered with impuritiesand still soluble in water.

On coming out from the bath of sulfate of ammonia, the cellulose film isbrought immediately,without any long contact with the air, into a bathformed by a concentrated or non-concentrate water solution of sodiumchlorid or of ordinary sea salt. The impurities contained in the film,more paricularly sulfids and polysulfids are dissolved in thasaid waterin which they are consequently fitain id. Thence, and without the filmundergoingaiongcontactwith the air,

it is introduced into a third bath formed by a mineral acid for instances hfuri or bydrochloric acid diluted with Water. The concentration ofthis bath will vary from 5% to 40% acid in accordance with the durationof the time during which-the film Specification of Letters Patent.

Patented Jan. 10, 1911. 1909. Seria1No.509,190.

is kept in it, its thickness and temperature. In contact with themineral acid, cellulose to the thickness of the said film and to thetemperature. .Claims.

1. A process for the continuous manufacducing a layer or sheet of watersolution of cellulose into a water solution of a salt bringing about thecoagulationof the said layer; in immediately introducing the film thuscoagulated into a bath formed by a solution of a salt capable of keepingback the impurities of the film, the said treatment being immediatelyfollowed by the immersion of the film into a bath formed by a mineralacid, for the purpose of rendering the cellulose film insoluble; inwater by the decomposition of the cellulose salt; the o eration b ingterminated by washing in col and in t water. r I

2. A process for the continuous manufacture of cellulose films obtainedfrom water solutions of cellulose, more particularly-from solutions ofcellulose xanthate, consisting in introducing a layer of water solutionof cellulose into a Water solution of a salt promediately introducingthe film thus coagulated -into*a bath'formed by a WfittGISOllltlOIl ofsodium chlorid in order to remove the impurities, the said treatmentbeing immediately followed by the immersion of the film into a bathformed by a mineral acid, for the purpose of renderin the cellulose filminsoluble in water by the decomposition of the cellulose salt, theoperation being terminated by washing in cold and in hot water.

3. A process for the continuous manufacsolution of cellulose, moreparticularly from solutions of cellulosexanthate, consisting inint-roduclng a layer of water solution of cel-' I I lulosenntoaconcentrated water solution of Xanthate of sodium, if a solution ofviscose ture of cellulose films, consisting in introducing thecoagulation of the layer, in init sulfate of" ammonia, for the purposeofcording to-the speed of the film in the bath,

ture of cellulose film's obta'inedfrom water lution of sodium chloridfor removing the bringing about the coagulation of the layer; inimmediately introducing the film thus coagulated into a bath formed by awater soimpurities, the treatment in question ing immediately followedby the immersion of the film into a bath formed by a mineral acid, forthe purpose of rendering the cellulose film insoluble in water by thedecomposition of the cellulose salt, the operation terminating inwashing in cold and in hot water.

l. A process for the continuous manufacture of cellulose filmsconsisting in introducing a layer of a water solution of celluloseXanthate into a bath of a concentrated Water solution of sulfate ofammonia'and permitting said layer to remain in said bath several minutesonly, whereby os1,sos

said layer is coagulated into a film soluble in Water, but preventedfrom conversion into cellulose, then immediatelyintroducing the filminto a bath of Water solution of sodium chlorid and dissolving out theimpurities contained in said film, then introducing said film into abath of mineral acid, thus converting the coagulated film soluble inwater into cellulose insoluble in water, and finally Washingthe film incold and in hot water.

In testimony whereof I have signed this specification in the presence oftwo subscrioing witnesses.

EDWIN BRANDENBERGER Witnesses: I

EMILE LEDRET,

